Bimetallic catalytic synthesis of annelated benzazepines

Abstract

A novel short synthetic route to annelated benzazepines, using additive enhanced palladium-indium catalytic 3-component cascade methodology is described.

Transition metals in organic synthesis: Highlights for the year 2005

“…Palladium-indium catalyzed the formation of fused benzazepines from isoquinolines, 1,2-butadiene, and 2-iodobenzylbromide (Eq. (55)) [496]. Palladium catalyzed an oxidative addition-intermolecular allene insertion-nucleophilic addition sequence using malonitriles as nucleophiles [497].…”

Synthesis of Novel Tetrahydrobenzazepine Derivatives and Their Cytoprotective Effect on Human Lymphocytes

“…The quaternary iminium salt was further reacted with allylmagnesium bromide to afford 1‐allylated compound 2 . The final step, cyclisation process, carried out under typical Heck conditions afforded tetrahydrobenzazepine derivative of β‐carboline 3 with exocyclic styrene‐like double bonds in 40% yield .…”

“…3,4‐Dihydro ‐ β‐carboline and 6,7‐dimethoxy‐isoquinoline were synthesised following the literature procedure , while compounds 4a , 7a , 7b , 8 , 12 and 15 were made by modified literature procedures.…”

“…3,4-Dihydro-b-carboline and 6,7-dimethoxy-isoquinoline were synthesised following the literature procedure [40][41][42][43], while compounds 4a [28,44], 7a [11], 7b [11], 8 [44], 12 [28] and 15 [45] were made by modified literature procedures. General procedure for the preparation of iminium salts Heterocyclic compound (3,4-dihydro-b-carboline, isoquinoline, pyridine) (2.5 mmol) and bromide (bromobenzyl bromide, allyl bromide) (2.8 eq) were heated in acetonitrile (10 mL) at 80°C for 4 h. The mixture was then cooled to room temperature, acetonitrile was removed under reduced pressure and crude salt was washed with dry diethyl ether (3 Â 5 mL).…”

“…In creating a new structural type we opted for the concept of privileged structure and selected tetrahydrobenzazepine (Fig. 2) as the core [8][9][10][11][12]. The skeleton of this heterocycle appears in many natural products with a range of biological properties [13][14][15][16][17][18].…”